#include "stdafx.h"

/*
 * -- SuperLU routine (version 2.0) --
 * Lawrence Berkeley National Lab, Univ. of California Berkeley,
 * and Xerox Palo Alto Research Center.
 * September 10, 2007
 *
 */
#include <math.h>
#include "hnum_pdsp_defs.h"
namespace harlinn
{
    namespace numerics
    {
        namespace SuperLU
        {
            int dlacon_(int *n, double *v, double *x, int *isgn, double *est, int *kase)
            {
            /*
                Purpose   
                =======   

                DLACON estimates the 1-norm of a square matrix A.   
                Reverse communication is used for evaluating matrix-vector products. 
  

                Arguments   
                =========   

                N      (input) INT
                        The order of the matrix.  N >= 1.   

                V      (workspace) DOUBLE PRECISION array, dimension (N)   
                        On the final return, V = A*W,  where  EST = norm(V)/norm(W)   
                        (W is not returned).   

                X      (input/output) DOUBLE PRECISION array, dimension (N)   
                        On an intermediate return, X should be overwritten by   
                                A * X,   if KASE=1,   
                                A' * X,  if KASE=2,
                        and DLACON must be re-called with all the other parameters   
                        unchanged.   

                ISGN   (workspace) INT array, dimension (N)

                EST    (output) DOUBLE PRECISION   
                        An estimate (a lower bound) for norm(A).   

                KASE   (input/output) INT
                        On the initial call to DLACON, KASE should be 0.   
                        On an intermediate return, KASE will be 1 or 2, indicating   
                        whether X should be overwritten by A * X  or A' * X.   
                        On the final return from DLACON, KASE will again be 0.   

                Further Details   
                ======= =======   

                Contributed by Nick Higham, University of Manchester.   
                Originally named CONEST, dated March 16, 1988.   

                Reference: N.J. Higham, "FORTRAN codes for estimating the one-norm of 
                a real or complex matrix, with applications to condition estimation", 
                ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988.   
                ===================================================================== 
            */

                /* Table of constant values */
                int c__1 = 1;
                double      zero = 0.0;
                double      one = 1.0;
    
                /* Local variables */
                static int iter;
                static int jump, jlast;
                static double altsgn, estold;
                static int i, j;
                double temp;
                    
            #define d_sign(a, b) (b >= 0 ? fabs(a) : -fabs(a))    /* Copy sign */
            #define i_dnnt(a) \
	            ( a>=0 ? floor(a+.5) : -floor(.5-a) ) /* Round to nearest integer */

                if ( *kase == 0 ) {
	            for (i = 0; i < *n; ++i) {
	                x[i] = 1. / (double) (*n);
	            }
	            *kase = 1;
	            jump = 1;
	            return 0;
                }

                switch (jump) {
	            case 1:  goto L20;
	            case 2:  goto L40;
	            case 3:  goto L70;
	            case 4:  goto L110;
	            case 5:  goto L140;
                }

                /*     ................ ENTRY   (JUMP = 1)   
	                FIRST ITERATION.  X HAS BEEN OVERWRITTEN BY A*X. */
                L20:
                if (*n == 1) {
	            v[0] = x[0];
	            *est = fabs(v[0]);
	            /*        ... QUIT */
	            goto L150;
                }
                *est = dasum_(n, x, &c__1);

                for (i = 0; i < *n; ++i) {
	            x[i] = d_sign(one, x[i]);
	            isgn[i] = i_dnnt(x[i]);
                }
                *kase = 2;
                jump = 2;
                return 0;

                /*     ................ ENTRY   (JUMP = 2)   
	                FIRST ITERATION.  X HAS BEEN OVERWRITTEN BY TRANSPOSE(A)*X. */
            L40:
                j = idamax_(n, &x[0], &c__1);
                --j;
                iter = 2;

                /*     MAIN LOOP - ITERATIONS 2,3,...,ITMAX. */
            L50:
                for (i = 0; i < *n; ++i) x[i] = zero;
                x[j] = one;
                *kase = 1;
                jump = 3;
                return 0;

                /*     ................ ENTRY   (JUMP = 3)   
	                X HAS BEEN OVERWRITTEN BY A*X. */
L70:
#ifdef USE_VENDOR_BLAS
                dcopy_(n, &x[0], &c__1, &v[0], &c__1);
#else
                dcopy_(*n, &x[0], &v[0]);
#endif
                estold = *est;
                *est = dasum_(n, v, &c__1);

                for (i = 0; i < *n; ++i)
	            if (i_dnnt(d_sign(one, x[i])) != isgn[i])
	                goto L90;

                /*     REPEATED SIGN VECTOR DETECTED, HENCE ALGORITHM HAS CONVERGED. */
                goto L120;

            L90:
                /*     TEST FOR CYCLING. */
                if (*est <= estold) goto L120;

                for (i = 0; i < *n; ++i) {
	            x[i] = d_sign(one, x[i]);
	            isgn[i] = i_dnnt(x[i]);
                }
                *kase = 2;
                jump = 4;
                return 0;

                /*     ................ ENTRY   (JUMP = 4)   
	                X HAS BEEN OVERWRITTEN BY TRANDPOSE(A)*X. */
            L110:
                jlast = j;
                j = idamax_(n, &x[0], &c__1);
                --j;
                if (x[jlast] != fabs(x[j]) && iter < 5) {
	            ++iter;
	            goto L50;
                }

                /*     ITERATION COMPLETE.  FINAL STAGE. */
            L120:
                altsgn = 1.;
                for (i = 1; i <= *n; ++i) {
	            x[i-1] = altsgn * ((double) (i - 1) / (double) (*n - 1) + 1.);
	            altsgn = -altsgn;
                }
                *kase = 1;
                jump = 5;
                return 0;
    
                /*     ................ ENTRY   (JUMP = 5)   
	                X HAS BEEN OVERWRITTEN BY A*X. */
            L140:
                temp = dasum_(n, x, &c__1) / (double) (*n * 3) * 2.;
                if (temp > *est) {
#ifdef USE_VENDOR_BLAS
	            dcopy_(n, &x[0], &c__1, &v[0], &c__1);
#else
                dcopy_(*n, &x[0], &v[0]);
#endif
	            *est = temp;
                }

            L150:
                *kase = 0;
                return 0;

            } /* dlacon_ */
        };
    };
};